/*=========================================================================

Program:   Visualization Toolkit
Module:    vtkMeanValueCoordinatesInterpolator.h

Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
All rights reserved.
See Copyright.txt or http://www.kitware.com/Copyright.htm for details.

This software is distributed WITHOUT ANY WARRANTY; without even
the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
PURPOSE.  See the above copyright notice for more information.

=========================================================================*/
// .NAME vtkMeanValueCoordinatesInterpolator - compute interpolation computes
// for closed triangular mesh
// .SECTION Description
// vtkMeanValueCoordinatesInterpolator computes interpolation weights for a
// closed, manifold polyhedron mesh.  Once computed, the interpolation
// weights can be used to interpolate data anywhere interior or exterior to
// the mesh. This work implements two MVC algorithms. The first one is for 
// triangular meshes which is documented in the Siggraph 2005 paper by Tao Ju, 
// Scot Schaefer and Joe Warren from Rice University "Mean Value Coordinates 
// for Closed Triangular Meshes". The second one is for general polyhedron
// mesh which is documented in the Eurographics Symposium on Geometry Processing
// 2006 paper by Torsten Langer, Alexander Belyaev and Hans-Peter Seidel from
// MPI Informatik "Spherical Barycentric Coordinates".
// The filter will automatically choose which algorithm to use based on whether
// the input mesh is triangulated or not.
//
// In VTK this class was initially created to interpolate data across
// polyhedral cells. In addition, the class can be used to interpolate
// data values from a polyhedron mesh, and to smoothly deform a mesh from 
// an associated control mesh.

// .SECTION See Also
// vtkPolyhedralCell

#ifndef __vtkMeanValueCoordinatesInterpolator_h
#define __vtkMeanValueCoordinatesInterpolator_h

#include "vtkObject.h"

class vtkPoints;
class vtkIdList;
class vtkCellArray;
class vtkDataArray;

//Special internal class for iterating over data
class vtkMVCTriIterator;
class vtkMVCPolyIterator;


class VTK_FILTERING_EXPORT vtkMeanValueCoordinatesInterpolator : public vtkObject
{
public:
  // Description
  // Standard instantiable class methods.
  static vtkMeanValueCoordinatesInterpolator *New();
  vtkTypeMacro(vtkMeanValueCoordinatesInterpolator,vtkObject);
  void PrintSelf(ostream& os, vtkIndent indent);

  // Description:
  // Method to generate interpolation weights for a point x[3] from a list of
  // triangles.  In this version of the method, the triangles are defined by
  // a vtkPoints array plus a vtkIdList, where the vtkIdList is organized
  // such that three ids in order define a triangle.  Note that number of weights
  // must equal the number of points.
  static void ComputeInterpolationWeights(double x[3], vtkPoints *pts, 
                                          vtkIdList *tris, double *weights);
  
  // Description:
  // Method to generate interpolation weights for a point x[3] from a list of
  // polygonal faces.  In this version of the method, the faces are defined by
  // a vtkPoints array plus a vtkCellArray, where the vtkCellArray contains all
  // faces and is of format [nFace0Pts, pid1, pid2, pid3,..., nFace1Pts, pid1, 
  // pid2, pid3,...].  Note: the number of weights must equal the number of points.
  static void ComputeInterpolationWeights(double x[3], vtkPoints *pts, 
                                          vtkCellArray *tris, double *weights);
protected:
  vtkMeanValueCoordinatesInterpolator();
  ~vtkMeanValueCoordinatesInterpolator();

  // Description:
  // Internal method that sets up the processing of triangular meshes.
  static void ComputeInterpolationWeightsForTriangleMesh(
    double x[3], vtkPoints *pts, vtkMVCTriIterator& iter, double *weights);

  // Description:
  // Internal method that sets up the processing of general polyhedron meshes.
  static void ComputeInterpolationWeightsForPolygonMesh(
    double x[3], vtkPoints *pts, vtkMVCPolyIterator& iter, double *weights);
  

private:
  vtkMeanValueCoordinatesInterpolator(const vtkMeanValueCoordinatesInterpolator&);  // Not implemented.
  void operator=(const vtkMeanValueCoordinatesInterpolator&);  // Not implemented.
};

#endif
